### Identification Dressed in a shade of crimson so intense it almost vibrates against the reef’s shadows, the Atlantic Bigeye (*Priacanthus arenatus*) is a master of color. Growing to about 14 inches, it possesses a deep, laterally compressed body and a steeply upturned mouth. Its most arresting feature, however, is its massive, gold-rimmed eyes—designed to harvest every stray photon of light. To distinguish it from the similar Glasseye Snapper, look at the fins and scales: the Atlantic Bigeye lacks the distinct dark spots on its pelvic and anal fins and has a much more uniform, velvety red appearance. Under stress or at rest, it can instantly shift its hue to a mottled pale pink or silver.
### Habitat & Range This species is a true Atlantic specialist, found from the chilly waters of Massachusetts down to Argentina, and across the pond to the West African coast. You’ll find them patrolling coral reefs and rocky jetties at depths of 30 to 100 feet, though they occasionally venture down to 300 feet. They are "crevice-dwellers," favoring the vaulted ceilings of underwater caves and the jagged silhouettes of shipwrecks.
### Behaviour By day, the Bigeye is the "Night Watchman" of the reef. You will likely spot them hovering near-motionless under ledges, often in small, loose aggregations. They are wary but curious, often tilting their bodies to keep a massive eye fixed on a passing diver. When the sun sets, their lethargy vanishes. They become solitary, active hunters, moving into the water column to intercept prey.
### Diet The Atlantic Bigeye is a specialized carnivore, focusing on the "drifters." It feeds primarily on pelagic crustaceans (like crab larvae and shrimp), small fish, and polychaete worms. Its large mouth acts as a vacuum, snapping shut on unsuspecting zooplankton that venture too close to the reef edge under the cover of darkness.
### Fascinating Fact If you catch a Bigeye in your dive light at night, its eyes will shine with a brilliant, eerie reflection. This is due to the *tapetum lucidum*, a reflective layer behind the retina (similar to a cat’s) that bounces light back through the photoreceptors, giving them exceptional night vision that far exceeds most of their predators!